Data storage systems typically store data on physical media in a manner that is transparent to host computers. From the perspective of a host computer, data is stored on virtual storage devices that are commonly known as logical volumes. Logical volumes are typically configured to store the data required for a specific data processing application. Data storage systems map logical volumes to addressable physical locations on storage media, such as direct-access hard disks.
System administrators frequently make copies of logical volumes, for example in order to perform backups or to test and validate new applications. Such copies are commonly referred to as snapshots.